We are examining the following reactions catalyzed by microsomal preparations from etiolated seedlings of sorghum, flax, and California poppy: (1) The N-hydroxylation of L-tyrosine, L-valine and L-isoleucine. (2) The beta-hydroxylation of p-hydroxyphenylacetonitrile and isobutyronitrile. (3) The oxidative decarboxylation of N-hydroxytyrosine and N-hydroxyvaline. We also are examining the following reactions which occur in Melilotus alba during the metabolism of aromatic compounds involved in coumarin metabolism: (1) The deamination of L-phenylalanine. (2) The o-hydroxylation of trans-cinnamic acid.